The invention relates to a monitoring device for monitoring the formation of sheets at individual feeder stations for collating machines and for the release of a control impulse for defective formation of bookblocks.
A device is known according to DD-PS No. 58 058, in collating machines furnished with feed grippers, which stops the operation of the drive of the machine as soon as the grippers catch either no sheet or a double sheet in an operating phase. This device is furnished with two contact pairs, disposed upon a contact lever, which are closed in the precalculated position of the contact lever. The contact pairs are included for a short time in the circuit of the control device by a switching device controlled by the single revolution shaft of the machine. According to the setting of two set screws, the contact opens by means of a contact spring when the contact lever, furnished with contact pairs, deviates from the precalculated position. By this process, the circuit is interrupted when double sheets or defective sheets arrive and the machine is stopped.
The adaptation of the described sheet control-and switching-device to the processing of papers of differing thicknesses is carried out by adjusting the stop screws. The disadvantage here is that the two stop screws have to be manually adjusted at each feed station.
The object of the invention is to accomplish monitoring of the formation of bookblocks at individual feed stations for collating machiines furnished with suction drums and having high cycle rates and to release a control impulse when faulty formation of bookblocks occurs, along with reducing expenses for setting the device for processing of paper of varying thicknesses.
Thus, the invention is based upon the object of creating a device for monitoring the formation of bookblocks in such a manner, that the precalculated position of a contact lever corresponding to any thickness of paper may simply be set upon the base plate and that the smallst deviations of the contact lever in one or the other direction are detected while ensuring regularity of signal and avoiding the influence of vibrations at high cycle rates.